Many types of electrical connector systems are used for interconnecting electrical and electronic components by inserting an electrical pin-type terminal into an electrical socket thereby electrically coupling two system locations. Usually, connectors used in such systems include some form of connector block of insulating material having a plurality of connector pins of electrically conductive material inserted through a plurality of pin receiving openings in the block. The openings may be in a given array or a designated pattern, such as one or more rows. The connector block usually is unitarily molded of plastic material or the like and may comprise the header or "wafer" for locating the terminal pins in proper positions for mating or connecting to a complementary electrical or electronic component.
Still further, attempts have been made to design connector blocks used in such systems so that they are somewhat universal for receiving different configurations of terminal pins. For instance, square pin receiving openings can receive both a square terminal pin and a round terminal pin, with the sides of the square pin and the diameter of the round pin being substantially the same dimensions as the cross-dimensions of the square openings, thereby providing an interference fit with both pin configurations. One of the problems with such systems, particularly in using square or rectangular terminal pins in corresponding square or rectangular openings is that the sides of the pins tend to scrape plastic particles from the sides of the connector block openings. This can happen during initial assembly or particularly during repeated repairs of the connector. The scraped particles or "shavings" accumulate on the pin heads and interfere with the interconnections between the pins and mating electrical terminals.
One approach to solving the problem of particle accumulator is to design the square or rectangular pins in what is commonly termed "starred" configurations. A starred terminal pin is fabricated by disrupting the metal corners of square or rectangular pins so that the corners project outwardly from the sides of the pins. The connector blocks are provided with square or rectangular openings sized such that the starred corners of the pins are disposed in the corners of the openings, with the sides of the pins spaced from the sides of the openings and thereby eliminate some of the scraping problems of the pins against the plastic material surrounding the openings. However, this approach detracts from the desirability of providing a universal system for accommodating a variety of terminal pins, because either the opening has to be enlarged or the body of the rectangular pins must be made smaller.
Other problems are encountered with connector systems utilizing connector blocks having pin receiving openings, particularly in multi-terminal connectors. Specifically, such connectors often include a series of terminal pins in a row or a plurality of rows. In miniature connectors, the pins are very closely spaced and the openings are separated by relatively thin wall portions of the connector block. It is not uncommon to encounter square pins on the order of 0.025 inch or round pins having 0.025 diameters. Because the pins are inserted into the openings with an interference fit, breaking or cracking of the walls between the openings in such miniature high-density connectors is a continuing problem. This can be understood when it is considered that it would not be uncommon to have as many as forty pins in a single row. The forces created by the interference fits of the pins in their respective openings multiply along the length of the row block, creating stresses which tend to crack the block particularly in the area of the walls or partitions between the pin receiving openings.
This invention is directed to solving all of the above problems by providing a connector block designed with a unique configuration for the pin receiving openings which can accommodate square, round or starred terminal pins and which significantly reduces stresses in the connector block.